Chen Lin-Ling, Yang Yi-Ming, Ji Guo-Ping
Department of Orthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China.
Shanghai Kou Qiang Yi Xue. 2008 Feb;17(1):25-9.
To evaluate the effect of maxillary protration in skeletal anterior crossbite patients in early permanent dentition and determine the optimal timing for orthopedic treatment.
18 patients (11 males and 7 females with a mean age of 11.5 years) with concave profile were treated with protraction headgear. For each patient lateral cephalogram was taken before and after treatment. Cephalometric analysis was carried out by using linear and angular measurements. Statistical analysis was performed using SAS6.12 software package.
All subjects were treated to normal overjet. SNA was increased by 2.06 degrees (P<0.001) ,A point was protruded by 3.94 mm(P<0.001), U1-SN was increased by 6.97 degrees (P<0.001).SNB was decreased by 1.39 degrees (P<0.01),SN-MP was increased by 2.64 degrees (P<0.001),Y axis was increased by 2.42 degrees (P<0.001), Pg point was decreased by 7.42 mm(P<0.001). Maxillary incisor was promoted by 6.86 mm,which was a result of 57.43% skeletal change and 42.57% dental change.
Maxillary protraction can significantly promote maxillary growth, change mandibular growth direction and inhibit mandibular protrusion in early permanent dentition.
